1. Field of the Invention
The present invention relates to a developing device provided in an electrophotographic recorder.
2. Description of the Related Art
An electrophotographic recorder used as a copying machine, a facsimile, a laser printer, etc has a charger, an exposure device, a developing device, a transfer device, and a fixing device sequentially arranged around a photosensitive drum in its rotating direction.
In the operation of the recorder, the photosensitive drum is caused to rotate, the exposure device exposes the charged surface of the rotating drum to form a latent image, the developing device develops the latent image on the surface of the rotating drum with toner to form a toner image the transfer device transfers the toner image from the surface of the drum to a recording paper, and the fixing device fixes the toner image on the recording paper.
The developing device provided in the electrophotographic recorder stores toner in its device body and supplies toner from the device body to the surface of the photosensitive drum.
When the toner in the device body is exhausted, toner is supplied into the device body.
In one method to supply toner into the device body of the developing device, an exchangeable toner cartridge is used.
The toner discharge port of the toner cartridge is covered with a strip-shaped sheet.
When the toner cartridge is mounted in the device body of the developing device, the flange of the toner cartridge is inserted to the guide rails of the device body, and the toner cartridge is slid along the guide rails of the device body until the front flange of the toner cartridge contacts and fits into the stopper of the device body.
The toner discharge port of the toner cartridge then coincides with the toner reception port of the device body.
The externally projecting end of the strip-shaped sheet is pulled by the operator to separate the strip-shaped sheet from the toner cartridge, so that the toner discharge port is opened, and the toner stored in the toner cartridge is discharged from the opened toner discharge port into the device body through the ports.
When the toner in the device body 8 of the developing device is exhausted, the front edge of a cartridge cover 16' is connected to the edge 15 of the device body 8, and the toner cartridge 19' is slid along the guide rails 17 of the toner cover 16' and the guide rails 17 of the device body 12, until the front flange of the toner cartridge 19' is located at the stopper piece 18, as shown in FIG. 11.
However the conventional cartridge cover has the following problems.
The cartridge cover of the conventional developing device is made from a material which is flexible, for example vinyl chloride.
Thus the edge of the cartridge cover 16' is sometimes caught on the edge of the toner discharge port 20, when the toner cartridge 19' is slid from the upper portion of the device body 8 to the base 16a of the cartridge cover 16' and the base 16a of the cartridge cover 16' is bent inward toward the toner cartridge 19' as shown in FIG. 12(b).
As shown in FIG. 13, the edge 16z of the conventional cartridge cover 16' is vertical to the direction in which the toner cartridge is removed from the device body to the cartridge cover.
And as shown in FIG. 14, the edge 19z of the conventional toner cartridge 19' is vertical to the direction in which the toner cartridge is removed from the device body to the cartridge cover.
When the base 16a of the cartridge cover 16' is bent inward toward the toner cartridge 19', the edge 16z of the cartridge cover 16' is caught on the edge 19z of the toner discharge port 20, and the base 16a of the cartridge cover 16' doesn't cover the toner discharge port 20 perfectly.
The toner resting in the toner cartridge 19' thus leaked out of the gap between the toner cartridge 19' and the device body 8.